Power lawn mowers typically incorporate various controls on the mower handlebar for controlling various systems on the mower. For example, one such control might be for controlling the mower engine operating speed. This particular control might include a pivotable lever mounted on the handlebar wherein a portion of the handle is connected to the mower engine speed control lever by a bowden cable. Movement of the lever varies the position of the engine speed control lever which, in turn, varies the actual engine speed. Movement of the pivotable lever might also control the position of the choke butterfly valve within the carburetor.
Another typical control on a mower handlebar might be a pivotable control bail mounted on the handlebar wherein the pivoting bail is connected to a mower self-propel system. Pivoting the control bail from one position to another would engage or disengage the mower self-propel drive system. The self-propel pivoting control bail can be connected to the self-propel engagement system by a bowden cable or a series of interconnected rods. Movement of the bail moves the bowden cable or rods and, thus, engages or disengages the mower self-propel system.
Still another control on a mower handlebar might be another pivotable control bail mounted on the handlebar wherein the pivoting control bail is connected to a mower zone brake system. Zone brake systems are utilized on power rotary lawn mowers to stop the engine and blade in a short period after the operator releases the zone brake pivoting control bail, either intentionally or inadvertently. Movement of the pivoting zone brake control bail to its operating position releases the engine and blade brake and also energizes the engines ignition system. Movement of the pivoting zone brake control bail to its non-operating or braking position brakes the engine and blade and also deenergizes the engine ignition system, stopping the rotating blade within a few seconds. This pivoting control bail is typically connected to the zone brake system by a bowden cable.
If the mower is equipped with a blade brake clutch in lieu of a zone brake, the blade brake clutch is also typically operated by a pivoting control bail mounted on the mower handlebar. Movement of the pivoting control bail engages or disengages the blade brake clutch which, in turn, brakes or releases the rotating cutting blade. The pivoting control bail and the blade brake clutch are usually connected by a bowden cable.
It is highly desirable to have the handlebar controls configured so that the operator can easily control the various systems on the mower. The prior art discloses several versions of control systems and are outlined below. One prior art lawn mower zone brake control system is disclosed in U.S. Pat. No. 5,088,273 issued to Braun et al on Feb. 18, 1992. In Braun, the lawn mower includes a handlebar 14 with a pivoting control bail 20 that is connected to a zone brake system, presumably by a bowden cable (not shown). The zone brake is released when the pivoting control bail 20 is pulled upward to the handlebar 14. When the pivoting control bail 20 is released, the bail swings down and away from the handlebar 14 engaging the zone brake and stopping the blade and the engine. Braun does not disclose a self-propel system.
Another prior art control system is disclosed in U.S. Pat. No. 4,327,539 issued to Bricko et al on May 4, 1982. In Bricko, a single pivoting control arm 10 is pivotally mounted on the mower handlebar 4. The single pivoting control arm 10 is connected to the mower blade brake clutch and to the mower self-propel system. To engage the mower self-propel system, the operator must pivot the arm 10 up and toward the handlebar. To stop the mower self-propel system, the operator must release the control arm 10 which is biased toward the neutral position. To release the blade brake clutch so that the engine can drive the blade, the operator must pivot the control arm 10 down and away to the position shown in FIG. 2 and then pivot the control arm 10 up toward the handlebar 10. As the control arm is pivoted up to the handlebar 10, the blade will begin rotating and the self-propel system will become engaged. If the operator releases the control arm 10, the control arm will return to the position shown in FIG. 1 and the blade brake will stop the rotation of the blade and the self-propel system will be disengaged, stopping the propulsion of the mower. Bricko does not disclose a zone brake system.
Another prior art mower control system is disclosed in U.S. Pat. No. 5,086,890 issued to Turczyn et al on Feb. 11, 1992. Turczyn discloses a lawn mower with a pivoting control bail 2 mounted on a handlebar 4. Pivoting control bail 2 is connected to a zone brake assembly positioned adjacent to the flywheel 26 by a bowden cable 5. When the operator pivots the control bail 2 so that it is parallel with the handlebar 4, the zone brake is released and the ignition circuit is energized. At that point, the engine can be started and the cutting blade will rotate. When the operator releases the control bail 2, it will pivot to the position shown in FIG. 2 and the zone brake will stop the rotation of the engine and blade and will deenergize the ignition circuit. Turczyn does not disclose a self-propel system.
Toro Operator's Manual, Form #3312-248 Rev. A, copyright 1983 to The Toro Company, discloses a prior art lawn mower control system. Page 6 of this manual discloses a lawn mower with a pivoting control bail that is coupled to the handlebar assembly. The handlebar also includes a pivoting plastic stop. The pivoting control bail is connected, by bowden cables, to the mower self-propel system and also to the mower zone brake system. When the operator pivots the control bail up toward the handlebar assembly as shown in FIG. 10, the zone brake is released and the mower engine can be started. However, since the operator must now hold the control bail in that position to start the engine, he winds up having to straddle the gap between the handlebar and the control bail with his hand, which can be uncomfortable. To engage the self-propel system, the operator must rotate the plastic stop counterclockwise as shown in FIG. 11 and then must pivot the control bail further up to engage the self-propel system. If, while running the mower, the operator decides to "feather back" the engagement of the self-propel system (that is, semi-disengage the self-propel system to slow the propulsion speed of the mower), he can simply pivot the control bail slightly away from the handlebar to slip the drive belt in the self-propel system and slow the travel speed of the mower. However, if the operator pivots the control bail too far away from the handlebar, the plastic stop, which is biased in a clockwise direction, will rotate back to the position shown in FIG. 10 and will then prevent the control bail from being pivoted back to the position shown in FIG. 11. That means that the self-propel system is disengaged and cannot be reengaged until the operator rotates the plastic stop counterclockwise as shown in FIG. 11. This particular configuration makes it somewhat difficult for the operator to "feather" the self-propel system in and out since the control bail is subject to being locked out by the plastic stop if it is pivoted too far away from the handlebar. As discussed above, the operator can "feather" the self-propel system in and out to vary the travel speed of the mower by pivoting the control bail toward and away from the handlebar since the control bail is connected to the self-propel system's drive belt tensioning system. By pivoting the control bail, the operator winds up slipping and tightening the drive belt around the sheaves to reduce or increase the speed of the transmission input sheave which, in turn, reduces or increases the travel speed of the mower. In the case of a single speed transmission, this turns out to be the only means for varying the travel speed of the mower except, of course, for varying the speed of the mower engine. Thus, it is important to be able to easily feather the control bail in and out without locking out the self-propel system and without engaging the zone brake which would stop the engine and require restarting it. While this particular system permits such feathering, it does require that the operator exercise great care in not pivoting the control bail too far away from the handlebar which, if done, will lockout the self-propel system and, if it is pivoted away from the handlebar too far, might engage the zone brake which will kill the engine. Furthermore, if the control bail is pivoted too far away from the handlebar and the plastic stop is tripped, the operator will have to rotate the plastic stop again to unlock the self-propel system. Finally, if the operator chooses to operate the mower in a non-self-propel mode, then he cannot pivot the control bail all the way to the handlebar and must hold the control bail in the position shown in FIG. 10 which requires that the operator's hand straddle the gap between the control bail and the handlebar. This, of course could become quite uncomfortable after some time.
Another prior art lawn mower control system is disclosed in the Toro Operator's Manual, Form No. 3314-941, copyright to The Toro Company in 1991. In FIGS. 6 through 8 on page 6 of this manual, a lawnmower with a pivoting control bail coupled to the handlebar assembly is disclosed. A throttle control and a ground speed control are also pivotally coupled to the handlebar assembly. The control bail is coupled to the self-propel system and the zone brake by bowden cables. The ground speed control is also coupled to the self-propel system by a separate bowden cable. To start the mower, the operator must pivot the control bail up to the handlebar assembly to the run/drive position shown in FIG. 8. In this position, the zone brake is released and the mower can be started. To engage the self-propel system, the operator must then pivot the control bail slightly away from the handlebar to the run/shift position as shown in FIG. 8. At this point, the operator must pivot the ground speed control out of its neutral position and into one of three propel speeds. Then the operator must pivot the control bail to the run/drive position as shown in FIG. 8. From this point on, the operator can "feather" the self-propel system in and out of engagement by pivoting the control bail between the run/drive position and the run/shift positions. This "feathering" has the effect of slipping or tightening the drive belt between the engine and the transmission sheaves so as to increase or decrease the travel speed of the lawn mower. To disengage the self-propel system, the operator must pivot the control bail to the run/shift position, which will slip the drive belt enough to stop propulsion. The operator should also pivot the ground speed control back to its neutral position at that point. The operator can then either release the control bail completely to stop the mower engine or can choose to continue mowing by placing the control bail back in the run/drive position which will keep the engine and cutting blade running without the self-propel system engaged since the ground speed control is in neutral.
The present invention offers an alternate lawn mower zone brake and self-propel system. In particular, a preferred lawn mower zone brake and self-propel system according to the present invention incorporates a mower deck, a prime mover mounted on the deck, a cutting blade rotatably coupled to the prime mover, a ground engaging wheel rotatably coupled to and supporting the deck, a handlebar assembly operatively coupled to the deck, a pivoting control bail pivotally mounted on the handlebar assembly and pivotable between first and second positions, a power transmitting device connecting the prime mover and the transmission, a zone brake operatively coupled to the prime mover and to the pivoting control bail wherein the zone brake operates in either a first or a second mode and wherein the zone brake inhibits rotational movement of and power generation by the prime mover in the first mode and wherein the zone brake allows rotational movement of and power generation by the prime mover in the second mode wherein the zone brake operates in the first mode when the pivoting control bail is in the first position and operates in the second mode when the pivoting control bail is in the second position, and a selector mechanism movably coupled to the pivoting control bail and coupled to the transmission by a first bowden cable wherein the selector mechanism is movable between a first and a second position and wherein movement of the selector mechanism to its second position and movement of the pivoting control bail to its second position causes the power transmitting device to transmit power from the prime mover to the transmission and the ground engaging wheel and wherein movement of either the selector mechanism or the pivoting control bail out of its respective second position stops the transmission of power through the power transmitting device from the prime mover to the transmission and ground engaging wheel.